IMMUNE DISTURBANCES IN TREATMENT-RESISTANT DEPRESSION - MODULATION BYANTIDEPRESSIVE TREATMENTS

Recently, there were some reports that major depression is accompanied by significant alterations in the percentage and number of peripheral blood mononuclear cells (PBMCs), such as increased number of CD4(+) T cells, B cells (e.g. CD19(+), CD21(+)), number of leukocytes, monocyt es and neutrophils and an increased CD4(+)/CD8(+) T-cell ratio. The ai ms of the present study were to examine the number and percentage of P BMCs in major and treatment-resistant depressed (TRD) patients and the effects of antidepressant treatments on those PBMCs. Major depression was characterized by a significantly higher number of leukocytes and CD4(+) T-cells, a higher percentage of CD2(+) T cells and CD4(+) T cel ls, and a higher CD4(+)/CD8(+) T-cell ratio than normal controls. Pati ents with TRD had a significantly higher percentage of CD4(+) T cells and CD4(+)/CD8(+) T-cell ratio, and a significantly lower percentage o f CD8(+) T cells than non-TRD patients and normal controls. There were significant negative correlations between the length of the index epi sode or duration of illness and number or percentage of monocytes; Sub chronic treatment with antidepressants significantly reduced the numbe r of leukocytes and neutrophils, but had no effect either on the absol ute number of the other PBMCs or on the CD4(+)/CD8(+) T-cell ratio. Th e results suggest that (i) the higher CD4(+)/CD8(+) T-cell ratio in ma jor depression is a trait marker of that illness and of treatment resi stance; (ii) the increased numbers of leukocytes and neutrophils are s tate markers of depression and are reduced by 'subchronic' antidepress ant therapy; (iii) the number and percentage of monocytes decrease wit h respect to duration of illness and length of the index depressive ep isode. (C) 1997 by John Wiley & Sons, Ltd.